The present invention relates to a container for transporting and for storing semiconductor wafers situated in processing cassettes. More particularly, the present invention relates to containers comprising a bottom plate, a hood and means for non-positive locking of the hood and the bottom plate.
In semiconductor manufacture, semiconductor wafers are manufactured and further-processed under clean room conditions. Containers whose interior offers a clean room climate are therefore necessary for storing the semiconductor wafers and for transporting the semiconductor wafers to the various processing locations. To that end, the containers should be optimally tight and should not release any contaminating substances, for example exhalations of material, themselves.
Standardization rules for transport containers as recited in the publication of Document No. 1332 of Semiconductor Equipment and Materials Institute dated 10 Jan. 1986 serve the purpose of defining containers that are interchangeable, that comprise standardized dimensions for robot manipulation and that are suitable for the acceptance of standardized processing cassettes.
This publication also provides recommendations concerning the demands that the component parts of a transport container should meet. The recommended standardizations are summarized under the term "Standard Mechanical Interface for Wafer Cassette Transfer" standard (SMIF Standard).
A lockable container for transporting and for storing semiconductor wafers situated in processing cassettes comprising a bottom plate, a hood and at least two locking levers for non-positive locking of the hood and the bottom plate that meets the SMIF Standard is disclosed by U.S. Pat. No. 4,582,219. This container comprises a rigid semiconductor wafer holder secured to the inside wall of the hood, this holder touching the semiconductor wafers situated in the processing cassette when the container is in its closed condition. Given a closed container, further, the semiconductor wafer holder is also held by a lock situated at the bottom plate. One disadvantage of this container is that it comprises component parts that are fashioned such that they cause friction when opening and closing the container and during transport, whereby contaminating particles can be released. Moreover, the container does not comprise any seal element between bottom plate and hood that ensures the particle tightness of the container. When closing the container, the projecting edge of the bottom plate is merely pressed against the edge of the hood by the spring power of the locking levers.
European Patent Application 87117836.4 also discloses a transport container for transporting and for storing semiconductor wafers situated in a semiconductor wafer cassette. Although this transport container can be closed in a dust-tight fashion and comprises a friction-free semiconductor wafer holder, it has an involved, complex design comprising an interchangeable, bipartite inside container.
Transport containers for semiconductor wafers that are particle-tight, contamination-free, meet the SMIF Standard and are distinguished by a simple structure at the same time are not previously known.